Almost 9,000 runners are limbering up for Sunday's Plusnet Leeds Half Marathon - making it the biggest field in the event's 30 year history.
The event, which is organised by Jane Tomlinson's Run For All, has grown from humble beginnings to become one of the key dates in the region's sporting calendar.
Back in 1986, around 900 runners lined up for the race. With the field now increasing tenfold, the run is now believed to be the biggest half marathon ever held in Yorkshire.
As well as boasting a record field, the event is expected to raise hundreds of thousands of pounds for charity.
Among those taking part this year is John Convery, the first winner of the Leeds Half Marathon in a time of 1:06:59 - still one of the fastest in the event's history.
He said: "The event has developed a lot since those early days. It is fantastic that it has grown into such a popular race that always generates a wonderful atmosphere. I am really looking forward to this year's run."
Event lead Lucy Elsender said: "This will be the fourth time Run For All has staged the Plusnet Leeds Half Marathon and it's fitting that in its 30th year, we can announce that this is likely to be the biggest half marathon that Yorkshire has ever seen."
Among the thousands taking part will be some familiar faces including Rugby Union head coach Stuart Lancaster, former England footballer Danny Mills, racing driver Daniel Lloyd, BBC newsreaders George Riley and Nicola Rees and Sky TV favourite Bryn Law.
The half marathon route starts in The Headrow alongside Victoria Gardens, heads out of the city centre, takes in a section of the Ring Road and returns via Abbey Road and Kirkstall Road before finishing in Cookridge Street alongside Millennium Square.
For the first time, this year's event will be sponsored by award-wining home and broadband provider Plusnet.
The company already sponsors the Yorkshire Marathon and the Yorkshire Half Marathon-Sheffield which, along with the Leeds Half, are part of the lasting legacy of the late Jane Tomlinson CBE who raised almost £2m for charity through a series of endurance challenges, despite being diagnosed with incurable cancer.
Andy Baker, Plusnet's Chief Executive Officer, said: "The Leeds Half Marathon already enjoys an excellent reputation, both as a first class running event and a fantastic charity fundraiser.
"We are delighted to be involved and I would like to wish everyone involved the very best of luck."
This year's official partner charities are the Jane Tomlinson Appeal, Forget Me Not Children's Hospice, Martin House Children's Hospice, Marie Curie, Sue Ryder, Overgate Hospice, St Gemma's Hospice, CLIC Sargent, Leeds Children's Hospital Appeal and Macmillan Cancer Support. Runners can, however, choose to raise funds for any charity of their choice - or simply run for fun.
The event is supported by Plusnet, Leeds City Council, Asda Foundation, the Yorkshire Evening Post, Radio Aire, Run247.com, Runner's World, iPro Sport, banana kick and LTS.
To find out more about the Plusnet Leeds Half Marathon, go to www.theyorkshiremarathon.com. A limited number of places in the event will be available, in person, over the weekend.